This consists in a reversal of the relative positions of pulmonary artery and aorta, so that the former takes origin from the left ventricle and the latter from the right. The blood from the systemic veins is sent directly into the aorta without first passing through the lungs, and the right ventricle undergoes hypertrophy, and becomes like the left. In such cases the conditions of life are very unfavourable, and yet in one case life was prolonged for three years. Rokitansky has pointed out that even though the great vessels may be transposed, the position of the ventricular septum may be so altered as to restore the normal connections with right and left ventricles respectively.